JP6697564B2 - Electromagnetic motor and stage device - Google Patents

Description

(Cross-reference of related applications)
[001] This application claims the priority of European Patent Application No. 16155377.1 filed on February 12, 2016 and European Patent Application No. 16167411.4 filed on April 28, 2016. .. These are entirely incorporated herein by reference.

[002] The present invention relates to an electromagnetic motor, a polyphase linear motor, a polyphase planar motor, a stage, a lithographic apparatus, and a method for manufacturing a device.

[003] A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such cases, patterning devices, also called masks or reticles, may alternatively be used to generate the circuit pattern to be formed on the individual layers of the IC. This pattern can be transferred onto a target portion (eg comprising part of, one, or several dies) on a substrate (eg a silicon wafer). The transfer of the pattern is usually performed by imaging on a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. A conventional lithographic apparatus synchronizes the substrate parallel or anti-parallel to a given direction (the "scan" direction) with a so-called stepper, where each target portion is illuminated by exposing the entire pattern to the target portion in one go. And a so-called scanner, in which each target portion is illuminated by scanning the pattern with a beam of radiation in a given direction (“scan” direction) while scanning the target.

[004] The patterning device and the substrate are mounted on an object table that is positioned using a positioning device in order to synchronously scan the pattern with the radiation beam and the substrate with the patterned image. Typically, such positioning devices include a combination of electromagnetic actuators and motors. In a typical configuration, such a positioning device may include a short stroke module for accurate positioning of the patterning device or substrate over a relatively short distance in 6 degrees of freedom. Short stroke modules, including patterning devices or substrates, can be moved over relatively long distances by, for example, long stroke modules including one or more linear or planar motors. In the lithographic apparatus of the prior art, a multi-phase linear motor such as a three-phase motor or a planar motor is generally used in a moving magnet configuration as a long stroke module. The coil is connected to the fixed world and the magnet is movable with respect to the coil.

[005] The design of such long stroke modules must meet a wide variety of constraints, such as force requirements, available footprint constraints, and acceptable dissipation constraints.

[006] As another example of such a constraint that has to be met, the aim of these motors is to generate a constant force for a given current flowing through the coil, and hence the magnet to the coil. Can be said to be irrelevant to the position of. However, in practice, a constant force or motor constant is not feasible and ripple remains. This ripple can be caused by voltage design rules, mechanical design rules, manufacturability and / or serviceability. It has been found that in motors that can generate high accelerations up to 400 m / s ² , which require relatively large forces, this can result in up to 8% ripple, which is undesirable.

[007] It is desirable to improve the degree of freedom in the design of electromagnetic motors applied for positioning purposes.

[008] It is further desirable to provide a polyphase motor with reduced motor ripple as a function of magnet position relative to the coil.

[009] According to one embodiment of the present invention, a multi-phase motor,
Coil system,
A magnet system movable in a first main drive direction parallel to the coil system;
Equipped with
The coil system generates a magnetic field that interacts with the magnet system to move the magnet system relative to the coil system by a driving force in a first main drive direction,
The coil system includes a plurality of coil assemblies, each coil assembly having a first dimension in a first main drive direction and having a non-zero first dimension between adjacent coil assemblies when viewed in the first main drive direction. There is a gap of 1,
The magnet system includes a magnet assembly having an array of magnets, with adjacent magnets in the magnet assembly having opposite polarities,
The magnet assembly has a first dimension in the first main drive direction substantially equal to J times the first dimension of each coil assembly plus J / 2 times the first gap, and J Is a positive integer, a polyphase motor is provided.

[0010] According to another embodiment of the invention there is provided a lithographic apparatus comprising a polyphase motor according to the invention.

[0011] According to yet another embodiment of the present invention, there is provided a device manufacturing method using the polyphase motor according to the present invention.

[0012] According to still another embodiment of the present invention, which is an electromagnetic motor,
A magnet assembly configured to generate an alternating magnetic field having a magnetic pitch in a first direction;
A coil assembly including a plurality of coils configured to cooperate with a magnet assembly to generate a first force in a first direction, the plurality of coils being a first coil set and a second coil set. And a first coil pitch of the first coil set in the first direction is different from a second coil pitch of the second coil set in the first direction.
An electromagnetic motor is provided.

[0013] According to another aspect of the present invention, there is provided an electromagnetic motor,
A magnet assembly configured to generate a two-dimensional alternating magnetic field having a first magnetic pitch in a first direction and a second magnetic pitch in a second direction;
A coil assembly configured to cooperate with a magnet assembly to generate a first force in a first direction and a second force in a second direction, the plurality of coil assemblies for generating the first force. A first coil set including a first coil and a second coil set including a plurality of second coils for generating a second force, the first coil set for a first magnetic pitch A first coil pitch ratio R1 in the first direction is different from a second coil pitch ratio R2 in the second direction of the second coil set to a second magnetic pitch;
An electromagnetic motor is provided.

According to yet another aspect of the present invention, a stage device configured to position an object,
An object table configured to hold objects,
One or more electromagnetic motors according to the invention, configured to displace an object table;
There is provided a stage device including.

[0015] According to yet another aspect of the invention, a lithographic apparatus comprising:
An illumination system configured to condition a beam of radiation,
A support constructed to support a patterning device, the patterning device capable of patterning a cross-section of the radiation beam to form a patterned radiation beam, and
A substrate table constructed to hold the substrate,
A projection system configured to project the patterned beam of radiation onto a target portion of the substrate,
The apparatus is further provided with a lithographic apparatus according to the invention or comprising a stage device for positioning a support or a substrate table.

According to yet another aspect of the present invention, there is provided a device manufacturing method including transferring a pattern from a patterning device to a substrate, wherein transferring the pattern is performed by using a stage apparatus according to the present invention. A device manufacturing method is provided that includes positioning a patterning device or substrate.

[0017] Embodiments of the invention are described below with reference to the accompanying schematic drawings, in which corresponding reference numerals indicate corresponding parts, which are merely exemplary.

[0018] Figure 7 depicts a lithographic apparatus according to an embodiment of the invention. [0019] Figure 3 illustrates a polyphase linear motor according to one embodiment of the invention. 3 is a graph showing motor constants as a function of position for a polyphase linear motor similar to the motor of FIG. 2, but having a prior art arrangement. 3 is a graph showing motor constants as a function of position of the polyphase linear motor of FIG. [0022] Figure 1 shows a top view of a planar motor known in the prior art. [0023] FIG. 3 shows a top view of an electromagnetic motor according to an embodiment of the present invention. [0024] FIG. 6 shows a cross-sectional view of a coil assembly applicable to an electromagnetic motor according to an embodiment of the present invention. [0024] FIG. 6 shows a cross-sectional view of a coil assembly applicable to an electromagnetic motor according to an embodiment of the present invention. [0024] FIG. 6 shows a cross-sectional view of a coil assembly applicable to an electromagnetic motor according to an embodiment of the present invention. [0025] FIG. 6 shows a cross-sectional view of an electromagnetic motor according to another embodiment of the present invention.

[0026] Figure 1 schematically depicts a lithographic apparatus according to one embodiment of the invention. The apparatus is adapted to support an illumination system (illuminator) IL configured to condition a radiation beam B (eg UV radiation or any other suitable radiation) and a patterning device (eg mask) MA. A mask support structure (e.g., a mask table) MT connected to a first positioning device PM constructed and configured to accurately position the patterning device according to certain parameters. The lithographic apparatus is also constructed to hold a substrate (eg, a resist-coated wafer) W and is connected to a second positioning device PW that is configured to accurately position the substrate according to certain parameters. Includes (eg, wafer table) WT or “substrate support”. The lithographic apparatus is a projection system (eg, refractive projection) configured to project a pattern imparted to a beam of radiation B onto a target portion C (eg, including one or more dies) of a substrate W by a patterning device MA. The lens system) PS is further provided.

[0027] The illumination system includes refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any of them, for guiding, shaping, or controlling radiation. Various types of optical components such as combinations can be included.

[0028] The mask support structure supports, ie bears the weight of, the patterning device. The mask support structure holds the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithographic apparatus, and other conditions, such as whether the patterning device is held in a vacuum environment. The mask support structure can use mechanical, vacuum, electrostatic, etc. clamping techniques to hold the patterning device. The mask support structure may be, for example, a frame or a table, and may be fixed or movable as required. The mask support structure can ensure that the patterning device is in the desired position, for example with respect to the projection system. Any use of the terms "reticle" or "mask" herein may be considered synonymous with the more general term "patterning device."

[0029] The term "patterning device" as used herein is intended to refer to any device that can be used to pattern a cross section of a radiation beam, such as to create a pattern in a target portion of a substrate. It should be interpreted broadly. It has to be noted here that the pattern imparted to the radiation beam may not correspond exactly to the desired pattern in the target portion of the substrate, for example if the pattern comprises phase-shifting features or so-called assist features. Generally, the pattern imparted to the radiation beam will correspond to a particular functional layer of a device being created in a target portion, such as an integrated circuit.

[0030] The patterning device may be transmissive or reflective. Examples of patterning device include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography and include mask types such as binary masks, alternating phase shift masks, halftone phase shift masks, as well as various hybrid mask types. Be done. As an example of a programmable mirror array, a matrix array of small mirrors is used, each mirror being individually tiltable to reflect an incoming radiation beam in different directions. The tilted mirrors impart a pattern in a radiation beam which is reflected by the mirror matrix.

[0031] The term "projection system", as used herein, as appropriate to the exposure radiation used, or other factors such as the use of an immersion liquid or the use of a vacuum, for example, a refractive optical system, a reflective optical system. It should be broadly interpreted as encompassing any type of projection system, including systems, catadioptric systems, magneto-optical systems, electromagnetic and electrostatic optical systems, or any combination thereof. Any use of the term “projection lens” herein may be considered as synonymous with the more general term “projection system”.

[0032] As shown herein, the device is of a transmissive type (eg, using a transmissive mask). Alternatively, the device may be of the reflective type (eg using a programmable mirror array of the type mentioned above, or using a reflective mask).

[0033] The lithographic apparatus may be of a type having two (dual stage) or more substrate tables or "substrate supports" (and / or more than one mask table or "mask supports"). In such a “multi-stage” machine, additional tables or supports may be used in parallel, or one or more other tables or supports may be used while exposing for exposure. Preparatory steps can be performed. The two substrate tables WTa and WTb in the example of FIG. 1 illustrate this. Although the invention disclosed herein can be used stand-alone, it can provide additional functionality, especially in the pre-exposure measurement stage of either single-stage or multi-stage apparatus.

The lithographic apparatus may be of a type in which at least part of the substrate may be covered with a liquid having a relatively high refractive index, such as water, so as to fill the space between the projection system PS and the substrate W. The immersion liquid can also be applied to other spaces in the lithographic apparatus, for example between the mask MA and the projection system PS. Immersion techniques can be used in the art to increase the numerical aperture of projection systems. The term "immersion" as used herein does not mean that a structure such as a substrate must be submerged in the liquid, but rather that there is liquid between the projection system PS and the substrate W during exposure. Is.

[0035] Referring to Figure 1, the illuminator IL receives a radiation beam from a radiation source SO. The radiation source and the lithographic apparatus may be separate components, for example when the radiation source is an excimer laser. In such a case, the radiation source is not considered to form part of the lithographic apparatus, and the radiation beam is emitted from the radiation source SO with the aid of a beam delivery system BD, which comprises, for example, suitable guiding mirrors and / or beam expanders. Passed to IL. In other cases, the source may be an integral part of the lithographic apparatus, for example when the source is a mercury lamp. The radiation source SO and the illuminator IL may be referred to as a radiation system together with the beam delivery system BD if desired.

[0036] The illuminator IL may comprise an adjuster AD configured to adjust the angular intensity distribution of the radiation beam. Typically, the outer and / or inner radial extent (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution in the pupil plane of the illuminator can be adjusted. The illuminator IL may also include various other components such as an integrator IN and a capacitor CO. An illuminator may be used to condition the radiation beam to provide the desired uniformity and intensity distribution across its cross section.

[0037] The radiation beam B is incident on the patterning device MA (eg, mask) held on the support structure MT (eg, mask table) and is patterned by the patterning device MA. A beam of radiation B traversing the patterning device MA passes through a projection system PS, which focuses the beam onto a target portion C of the substrate W. With the aid of a second positioner PW and a position sensor IF (eg an interferometer device, a linear encoder or a capacitive sensor) to position the substrate table WTa / WTb eg the various target portions C in the path of the radiation beam B. Can be moved to exactly. Similarly, the first positioner PM and a separate position sensor (not explicitly shown in FIG. 1) are used to pattern the path of the radiation beam B, such as after mechanical removal from the mask library or during a scan. The device MA can be accurately positioned. In general, movement of the support structure MT can be realized with the aid of a long stroke module (coarse positioning) and a short stroke module (fine positioning) forming part of the first positioner PM. Similarly, movement of the substrate table WTa / WTb can be realized using a long stroke module and a short stroke module forming part of the second positioner PW. In the case of a stepper (as opposed to a scanner), the support structure MT may be connected to the short stroke actuator only or may be fixed. The patterning device MA and the substrate W can be aligned using the mask alignment marks M1, M2 and the substrate alignment marks P1, P2. The substrate alignment marks as shown occupy dedicated target portions, but may be located in the space between the target portions (known as scribe line alignment marks). Similarly, in situations in which more than one die is provided on the patterning device MA, the mask alignment marks M1, M2 may be located between the dies.

[0038] The depicted apparatus can be used at least in scan mode. In scan mode, the support structure MT and the substrate table WTa / WTb are scanned synchronously while the pattern imparted to the radiation beam is projected onto the target portion C (ie a single dynamic exposure). The speed and direction of the substrate table WTa / WTb with respect to the support structure MT can be determined by the (reduction) magnification and the image reversal characteristics of the projection system PS. In scan mode, the maximum size of the exposure field limits the width of the target portion (non-scanning direction) during single dynamic exposure, while the length of the scanning operation causes the height of the target portion (scanning direction) to increase. Decided.

[0039] In addition to the scan mode, the depicted apparatus may be used in at least one of the following modes:

[0040] 1. In step mode, the support structure MT and the substrate table WTa / WTb are kept essentially stationary, while the entire pattern imparted to the radiation beam is projected onto the target portion C at one time (ie a single static). Exposure). The substrate table WTa / WTb is then moved in the X and / or Y direction so that another target portion C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure.

[0041] 2. In another mode, the support structure MT holds the programmable patterning device and remains essentially stationary, projecting the pattern imparted to the radiation beam onto the target portion C while moving or scanning the substrate table WTa / WTb. To do. In this mode, a pulsed radiation source is typically used to update the programmable patterning device as needed each time the substrate table WTa / WTb is moved or between successive radiation pulses during a scan. This mode of operation is readily available for maskless lithography that utilizes programmable patterning device, such as a programmable mirror array of a type as referred to above.

[0042] Combinations and / or variations on the above described modes of use or entirely different modes of use may also be utilized.

The lithographic apparatus LA is a so-called dual stage type apparatus having two substrate tables WTa and WTb and two stations, an exposure station and a measurement station. The substrate table can be exchanged between these two stations. While the exposure station is exposing one substrate on one substrate table, the measuring station can load another substrate on the other substrate table to perform various preparation steps. The preparation step may include mapping the surface of the substrate with the level sensor LS and measuring the position of the alignment mark on the substrate with the alignment sensor AS. This allows a significant increase in device throughput. If the position sensor IF cannot measure the position of the substrate table while the substrate table is at the measuring station and the exposure station, a second position sensor is provided so that the position of the substrate table can be tracked at both stations. You can

[0044] The apparatus further includes a lithographic apparatus control unit LACU that controls the movement and measurement of all of the various actuators and sensors described. The control unit LACU also includes signal processing and data processing functions for implementing the desired calculations relating to the operation of the device. In practice, the control unit LACU is implemented as a system of many subunits, each handling real-time data acquisition, processing and control of subsystems or components within the device. For example, one processing subsystem may be dedicated to servo control of the substrate positioner PW. It is also possible that separate units handle the coarse and fine actuators or different axes. Another unit may be dedicated to reading the position sensor IF. Overall control of the apparatus can be controlled by a central processing unit that communicates with these subsystem processing units and also with operators and other devices involved in the lithographic manufacturing process.

[0045] FIG. 2 shows a three-phase linear motor 1 according to an embodiment of the present invention. In this embodiment, the three-phase linear motor is part of the long stroke module of the first positioner PM, but in addition or in the alternative, such a motor may be used in other parts of the lithographic apparatus. It will be appreciated that movement and positioning of objects, such as a substrate table constructed to hold a substrate, can be performed.

The motor 1 includes a first coil system 10 and a second coil system 20 arranged so as to face the first coil system 10. Throughout this description, when a "coil system" is used, it refers to both the first coil system 10 and the second coil system 20.

A magnet system 30 is arranged between the coil systems 10, 20. The magnet system is movable parallel to the coil system 10, 20 in a first main drive direction parallel to the X direction. The motor 1 generates a driving force in the first main driving direction by generating a magnetic field that interacts with the magnet system in the coil systems 10 and 20. By asymmetrically applying a current to the coil system 10, 20, the magnet system can also generate a force in the non-driving direction parallel to the Z direction, which is used by the magnet system to generate a force in the coil system 10, 20. It is possible to prevent collisions and / or to levitate objects attached to the magnet system.

The coil system 10, 20 includes a plurality of coil assemblies 11, 12, 13, 21, 22, 23. The coil assemblies 11, 12, 13 correspond to the first coil system 10, and the coil assemblies 21, 22, 23 correspond to the second coil system 20. Each coil assembly has a dimension L in a first main drive direction, the X direction, and adjacent coil assemblies have a non-zero first gap G therebetween when viewed in the first main drive direction. Have.

[0049] Each coil assembly 11, 12, 13, 21, 22, 23 is provided with two three-phase coils TC in this embodiment. Each three-phase coil provides three phases 14, 15, 16 as shown only in the upper three-phase coil TC of coil assembly 11.

[0050] The coil systems 10, 20 further include back irons 18, 28. These back irons perform the function of containing the magnetic field generated by the coil system, thus minimizing flux leakage and acting as a support element for the coil assembly.

[0051] The magnet system 30 in this embodiment includes a magnet assembly 31 having an array of magnets. Adjacent magnets in the magnet assembly have opposite polarities that are perpendicular to the coil assembly, ie, parallel to the non-driving direction (Z direction). These magnets can be formed by one or more sub-magnets, all having the same polarity. In this embodiment, the magnets are dimensioned such that four magnets face one 3-phase coil TC. Alternatively, the intermediate magnet may be positioned between magnets of opposite polarity. The intermediate magnets have polarities parallel to the drive direction, so as to form a Hallbach magnet array, for example.

Further, in this embodiment, the row 32 of first sub-magnets facing the first coil system 10 and the row 32 of second sub-magnets facing the second coil system 20 are both first and second. Form a magnet that interacts with both of the coil systems of, but any other configuration is also envisioned.

[0053] Preferably, the gap G between adjacent coil assemblies is zero or close to zero, ie close to the distance between the coils in the coil assembly. This is because the non-zero gap G disturbs the periodicity of the position of the three-phase coil TC with respect to the magnet. This produces a non-constant force as a function of position. An example of this is shown in FIG. FIG. 3 shows that the first dimension of the magnet system in the first main drive direction is equal to J times the first dimension L of each coil assembly (J is a positive integer as used in the prior art). In this case, a graph MC of the motor constant Km in Newton / ampere in the first main drive direction as a function of the position of the magnet system in the first main drive direction is shown. Ripple can easily be ± 8%.

[0054] The cause of the non-zero gap G is that the coil assembly can only include a limited number of three-phase coils TC, in this embodiment two coils TC, for manufacturability and maintainability. Can be When the coil assemblies are mounted together to form a coil system, there is a non-zero gap G between adjacent coil assemblies due to, for example, high voltage design rules for creepage and clearance, and mechanical design rules. It is determined that this is necessary, but this can lead to ripple.

[0055] Compared with the configuration of the prior art, the present invention can reduce the generated ripple by extending the magnet assembly. In the embodiment of FIG. 2, the first dimension in the first main drive direction provided to the magnet assembly 31 is J times the first dimension L of each coil assembly to J / 2 times the first gap G. Is substantially equal to J is a positive integer.

[0056] The extension in this embodiment may be a single magnet that at least partially compensates for the ripple. However, depending on the size of the magnet and the size of the gap G, the extension can be formed by more than one magnet.

[0057] An example of the effect of extension is shown in FIG. FIG. 4 shows a graph MC2 of the motor constant Km2 (in Newtons / Amps) in the first main drive direction as a function of the position of the magnet system 30 in the main drive direction. Since the scale of this graph is identical to that of the graph of FIG. 3, it is clear that a significant reduction in the ripple of the motor constant was obtained as a result of the extension of the magnet system. Ripple can be easily reduced to less than ± 0.5%.

[0058] Although the embodiment of FIG. 2 illustrates a coil system having three coil assemblies, it should be apparent that the coil system may have any number of coil assemblies.

[0059] The embodiment of Figure 2 shows a motor having first and second coil systems with a magnet system sandwiched between them, but only one of the two coil systems is adjacent to and in parallel with it. A motor in which the magnet system is arranged is also within the scope of the invention.

[0060] Although the described embodiment is a three-phase system, the present invention is applicable to any multi-phase linear motor, including, but not limited to, two-phase motors and four-phase motors.

[0061] While the described embodiments are described as solving / mitigating the problem of motor constant ripple in the main drive direction as a function of position in the drive direction, the present invention instead or instead of this. In addition, it can be applied to solve / mitigate the problem of motor constant ripple in the non-drive direction as a function of position in the drive direction.

[0062] Although the motor described in FIG. 2 may suggest that the present invention is only applicable to linear motors, the present invention provides that the coil system and the magnet system are perpendicular to both the X and Z directions. It can also be applied to a planar motor extending in the second main drive direction. The second main drive direction can alternatively be called the Y direction.

[0063] The coil assembly has a second dimension in a second main drive direction. There is a non-zero second gap between adjacent coil assemblies in the second main drive direction, and the second dimension of the magnet assembly in the second main drive direction is the same as the dimension in the first main drive direction. Similarly, it is substantially equal to K times the second dimension of each coil assembly plus K / 2 times the second gap. K is a positive integer.

[0064] According to another aspect of the invention, an electromagnetic motor that can be applied in a lithographic apparatus is described. Specifically, in a lithographic apparatus according to the invention, either or both of the first or second positioning device PW, PM are provided with one or more according to the invention for positioning a patterning device or a substrate. An electromagnetic motor can be included.

[0065] In one embodiment, the long stroke module of the second positioning device PW comprises a planar motor according to the invention. Typically, a substrate applied in a lithographic apparatus according to the invention has a horizontal plane, hereinafter referred to as the XY plane, in both the X and Y directions over a relatively long distance, for example 500 mm or more. It needs to be displaced.

[0066] Fig. 5 schematically shows a top view of a planar motor known in the prior art. The planar motor 200 comprises a magnet assembly 210 including a plurality of permanent magnets 210.1 configured to generate a spatial alternating magnetic field in two directions, the X and Y directions. The magnets shown as gray squares have the opposite magnetic polarization than the magnets shown as white squares. The alternating magnetic field has a magnetic pitch Pm in the X and Y directions. The planar motor 200 further produces forces in both the X and Y directions by applying the appropriate currents to the coils or coil sets 220.1, 220.2, 220.3, and 220.4 of the coil assembly 220. The coil assembly 220 configured as described above is provided. In the embodiment as shown, each coil set includes a triplet of coils, the coils having a coil pitch Pc in both the X and Y directions. In the embodiment as shown, the coil pitch Pc applied with the coils of the four coil set is equal to:

[0067] According to the present invention, the coil pitch or coil span can be referred to as the distance between the two coil sides applied to the electromagnetic motor along the direction of the alternating magnetic field, or the width of the coil. This can be expressed as a function of the magnetic pitch Pm, ie the width of the magnetic poles of the magnetic field distribution, as shown in equation (1). In the illustrated embodiment, the coil sets 220.1 and 220.3 are configured to generate a force in a first direction (X direction) and the coil sets 220.2 and 220.4 include a second direction. It is configured to generate a force in the (Y direction). As can be seen, the coil set adapted to generate a force in a first direction (X direction) is adapted to generate a force in a second direction (Y direction). Substantially equal in size to the coil set. Such an arrangement may be suitable if the force requirements on the motor are substantially equal in both directions.

[0068] However, in general, the force requirements may differ. Furthermore, there may be geometric constraints that limit the options that optimize the use of the area available for applying the coil or coil set. For this reason, simply shortening or lengthening the coil applying the force in the first direction as compared to the coil applying the force in the second direction may not be an appropriate or practical option. Thus, the present invention introduces another degree of freedom that can provide improved utilization of the available footprint of planar or linear motor coil assemblies. Within the meaning of the present invention, "footprint" is used to describe the available area in which the coils of a coil assembly can be located. FIG. 6 schematically shows a first embodiment of an electromagnetic motor according to the invention. The electromagnetic motor 400 according to the first embodiment of the present invention includes a magnet assembly 410 and a coil assembly 420 configured to cooperate with the magnet assembly 410, whereby a first direction (X direction). ) And a second direction (Y direction) a force is generated in the planar motor.

  In the illustrated embodiment, the magnet assembly comprises a plurality of permanent magnets configured to generate an alternating magnetic field with a magnetic pitch Pm1 in a first direction and a magnetic pitch Pm2 in a second direction. It can be pointed out that the Halbach magnet arrangement can be used to increase the magnetic strength of the spatial alternating magnetic field. In such a configuration, for example, a permanent magnet having magnetic polarization having a component parallel to the XY plane can be used. In the illustrated embodiment, the first magnetic pitch Pm1 is equal to the second magnetic pitch Pm2. However, it should be noted that this is not mandatory. That is, the first magnetic pitch Pm1 may be different from the second magnetic pitch Pm2. To generate a force in the Y direction, a coil assembly 420 of an electromagnetic motor according to the present invention includes a first coil set 420 including four triplets of coils 420.1, 420.2, 420.3, and 420.4. Is equipped with. The coils of the first coil set have a coil pitch Pc1. In order to generate a force in the X direction, the coil assembly 420 of the electromagnetic motor according to the present invention comprises a second coil set including two triplets of coils 420.5 and 420.6 having a coil pitch PC2. ..

In general, it can be pointed out that the electromagnetic motor according to the invention can be controlled to generate a force in a direction perpendicular to one or more directions of the alternating magnetic field. Therefore, by appropriately controlling the current supplied to the coil assembly 420, a force in the Z direction perpendicular to the XY plane can also be generated. According to this embodiment of the invention, unlike the planar motor as shown in FIG. 2, the ratio R1 of the coil pitch Pc1 to the magnetic pitch Pm1 is different from the ratio of the coil pitch Pc2 to the magnetic pitch Pm2.

When Pm1 = Pm2, the coil pitch Pc1 is different from the coil pitch Pc2. By doing so, the electromagnetic motor according to the present invention incorporates an additional degree of freedom that allows for more efficient use of the available footprint of the coil assembly 420. In the embodiment shown, the coil pitch Pc1 applied to the first coil set, eg the first triplet 420.1 of the coil, and the first coil set 420.5 or 420.6, for example. The coil pitch Pc2 applied to the two coil set is given by:

  Therefore, the coils of the second coil set are wider than the coils of the first coil set, that is, the coil pitch is larger for each magnetic pitch. The application of a larger coil pitch allows the same force to be generated at a smaller current density (assuming substantially the same coil height is applied), resulting in reduced power loss. Alternatively, if the same current density is applied, greater force is obtained. By choosing different ratios R1 and R2, the available footprint can be optimally filled with coils to meet the force requirements in both directions.

[0069] Better motor thermal behavior can also be obtained if the available footprint is substantially covered by the coil assembly. By allowing the selection of different ratios R1 and R2, the length of the coils used in the first and second directions can be adjusted so that the losses are more evenly distributed over the footprint. Due to the difference in force requirements and duty cycle between the first and second directions, the losses in both coil sets can be substantially different. However, the selection of different ratios R1 and R2 provides an additional degree of freedom to dimension the coils of both the first and second coil sets so as to balance the losses in both coil sets. .. Specifically, in one embodiment, a substantially uniform average power loss distribution is obtained across the footprint. As a result, a more uniform temperature distribution can be obtained in the entire coil assembly.

[0070] In a preferred embodiment, the coil set applied to the electromagnetic motor is arranged in a triplet, whereby the triplet is arranged to be powered by a three-phase power supply. In this regard, it should be pointed out that the need to power the coil set using a three-phase power supply limits the available options for the ratio of coil pitch to magnetic pitch.

[0071] Figure 7 (a) schematically illustrates a cross-sectional view of a portion of a magnet assembly 520 applicable to an electromagnetic motor according to the present invention. This portion of the magnet assembly includes four permanent magnets 520.1, 520.2, 520.3, and 520.4 that are alternately polarized (indicated by the arrows in the magnet) and have a magnetic pitch Pm. Have. FIG. 7 (a) further schematically shows a coil set 510 including three coils 510.1, 510.2 and 510.3 having a coil pitch Pc according to equation (1). That is, Pc is equal to 4/3 × Pm. Pm is the magnetic pitch of the magnet assembly 520. Thus, the configuration shown is similar to the layout of coil sets 420.1, 420.2, 420.3, or 420.4 for magnet assembly 410 of FIG. In FIG. 7A, reference numerals 522 and 524 indicate the directions of currents flowing in the coils. In the illustrated case, ie, where Pc equals 4/3 × Pm (magnetic pitch), the three coils 510.1, 510.2, and 510.3 of coil assembly 510 are connected to the R of the three-phase power supply. Phase, S phase, and T phase can be connected. In doing so, a substantially constant force can be generated between the magnet assembly 520 and the coil assembly 510 during use.

[0072] Figure 7 (b) schematically illustrates a cross-sectional view of a portion of a magnet assembly 620 applicable to an electromagnetic motor according to the present invention. This portion of the magnet assembly includes five permanent magnets 620.1, 620.2, 620.3, 620.4, and 620.5, which are alternately polarized (indicated by the arrow in the magnet). , Magnetic pitch Pm. FIG. 7 (b) further schematically illustrates a coil set 610 including three coils 610.1, 610.2 and 610.3 having a coil pitch Pc equal to 5/3 times the magnetic pitch Pm of the magnet assembly 620. Shown in. Thus, the configuration shown is similar to the layout of coil set 420.5 or 420.6 for magnet assembly 410 of FIG. In such a configuration, as indicated by reference numerals 622 and 624, if the direction of the current flowing through the second coil 610.2 is reversed, then the three coils of coil set 610 will still have three-phase power supply. Can be supplied by. This can be achieved, for example, by reversing the winding direction of the second coil 610.2 or by rotating the coil 180 degrees about an axis perpendicular to the plane of the drawing.

[0073] Fig. 7 (c) schematically shows still another method of applying different coil pitches, which is suitable for supply by a three-phase power supply. FIG. 7 (c) schematically illustrates a portion of a magnet assembly 720 that includes ten alternatingly polarized magnets configured to cooperate with a coil assembly 710 that includes six coils. Each coil has a coil pitch Pc equal to 5/3 × Pm, where Pm is the magnetic pitch of the magnets of magnet assembly 720. In the configuration as shown, the coils are grouped into two adjacent coil pairs, each pair of two adjacent coils, such as coils 710.1 and 710.2, having a three-phase power supply. It is supplied by the same phase (R phase, S phase, or T phase as shown). Such a coil pair has a pitch Pw called a winding pitch. This is equivalent to

By doing so, it is not necessary to reverse the direction of the current flowing in the coil supplied by the second phase, ie the S phase shown.

[0075] Regarding the embodiment shown in FIG. 7 (c), it is worth noting that coil pairs belonging to the same phase do not have to be supplied by the same power supply. Thus, a coil assembly 710 as shown may be powered by two 3-phase power supplies, for example, in one embodiment. For example, one three-phase power supply powers the left coil of each of the illustrated R, S, and T phases, while the other three-phase power supply illustrates the illustrated R, S, and Power the right coil of each of the T phases. In such a configuration, currents having different amplitudes or phase angles can be applied to coils belonging to the same phase, such as the coils 710.1 and 710.2.

[0076] FIGS. 6 and 7 (a) to 7 (c) illustrate the application of different coil pitches for different coil sets, for example applicable to the electromagnetic motor according to the first embodiment of the present invention. .. In this first embodiment, different coil pitches or different coil pitch ratios to the magnetic pitch are applied to different drive directions of the electromagnetic motor.

  However, in addition to applying different coil pitches in different driving directions, when using multiple coil sets per driving direction, different coil pitches are applied to these multiple coil sets, and thus available It is worth pointing out that further flexibility in filling the footprint may be advantageous. As an example, referring to FIG. 3, the four coil triplets 420.1, 420.2, 420.3, and 420.4 used to generate the force in the Y direction have the same coil pitch Pc1. No need. The coil triplets 420.1, 420.2, 420.3, and 420.4 can be grouped, for example, by coil sets having different coil pitches. As an example, consider coil triplets 420.1 and 420.4 as one coil set, apply pitch Pc1 to this coil set, and consider coil triplets 420.2 and 420.3 as another coil set and call Pc1. Can apply a different third coil pitch. In one embodiment, the third coil pitch may be selected equal to Pc2, for example. However, the third coil pitch can also be different from Pc2.

  Combining coil sets with different coil pitches can also be advantageous in linear motors. Therefore, in a second embodiment, the present invention provides a magnet assembly configured to generate an alternating magnetic field having a pitch Pm in a first direction, and a first magnet assembly in the first direction in cooperation with the magnet assembly. And a coil assembly including a plurality of coils, the electromagnetic motor being configured to generate a force. Accordingly, the plurality of coils are arranged in the first coil set and the second coil set, and the coil pitch Pc1 of the first coil set is different from the coil pitch Pc2 of the second coil set. FIG. 8 schematically shows a cross-sectional view of such a motor. FIG. 8 schematically illustrates a portion of a magnet assembly 820 of an electromagnetic motor according to the present invention. Magnet assembly 820 includes a plurality of alternatingly polarized permanent magnets, such as magnets 820.1 and 820.2 (polarization directions are indicated by arrows within the magnets). The electromagnetic motor further comprises a coil assembly 810 that includes a first coil set 812 and a second coil set 814. In the illustrated embodiment, the first coil set includes three coils, each coil has a coil pitch Pc1, the second coil set also includes three coils, and each coil has a coil pitch Pc2. .. In use, the coil assembly 810 can be configured to cooperate with the magnet assembly 820 to generate a force, for example, along the Y direction, ie, the same direction that the alternating magnetic field is generated by the magnet assembly 820. Generally, the first coil set 812 includes, for example, one or more coil triplets referred to as a first coil triplet, and the second coil set 814 also includes one or more coil triplets referred to as, for example, a second coil triplet. Coil triplets. In the illustrated embodiment, the respective coil pitches Pc1 and Pc2 of the first coil set 812 and the second coil set 814 satisfy the condition of Expression (3). Since each coil set has one coil triplet, the illustrated coil assembly 810 spans nine magnets, ie the magnetic pitch Pm, ie the distance between adjacent N and S poles of an alternating magnetic field. Is 9 times. Furthermore, it can be pointed out that the central coil of the second coil set 814 has the winding direction reversed, as in the coil set 610 of FIG. 7B. In such an embodiment, the coil triplets of the first coil set and the coil triplets of the second coil set may be configured to be powered by a common three-phase power supply. This allows the coils of the first coil triplet and the second coil triplet configured to be powered by the same phase of the three-phase power supply to be connected in series. In the illustrated embodiment, the coils 812.1 and 814.1 are connected in series, the coils 812.2 and 814.2 are connected in series, and the coils 812.3 and 814.3 are connected in series. You can In such an embodiment, it may be preferable to apply the same conductor dimensions in the first coil set and the second coil set. Specifically, the cross section of the coil windings of the first coil set can be selected to be substantially equal to the cross section of the coil windings of the second coil set. By doing so, when the coils of the coil triplet are connected in series as described above, the current densities can be kept substantially equal in both coil sets. This results in a substantially uniform loss in the coil assembly. In one embodiment, the coil winding height H of the first coil set is selected to be substantially equal to the coil winding height of the second coil set. By doing so, the back surface of the coil assembly, that is, the surface formed by the coil surface that does not face the magnets (shown by dotted line 850), is substantially flat, and provides a cooling mechanism common to both coil sets. Applicable.

With respect to the embodiment as shown in FIG. 8, it can be pointed out that by combining coil sets with different coil pitches, increased flexibility or design freedom can be obtained. As already mentioned, the overall width of the coil assembly as shown spans nine magnets. Such a width cannot be obtained when combining coil sets having the same coil pitch. Therefore, the electromagnetic motor according to the present invention, which applies a set of coils with different coil pitches to generate a force, has a high degree of design freedom regarding the overall width of the coil assembly for a given magnetic pitch. In one embodiment, this increase in design freedom can be realized by selecting Pc2 such that Pc1 <Pc2 <2 × Pc1.

[0078] The electromagnetic motor according to the present invention can be advantageously implemented in a stage device according to the present invention. In one embodiment, the invention provides a stage apparatus configured to position an object such as a patterning device or a substrate applied in a lithographic apparatus, for example. Such a stage device comprises an object table for holding an object to be positioned and one or more electromagnetic motors according to the invention for displacing the object table.

In one embodiment of the stage apparatus according to the present invention, the coil assembly of the applied electromagnetic motor is mounted on the object table. Alternatively, the magnet assembly of the applied electromagnetic motor may be mounted on the object table.

[0080] In one embodiment, the stage device further comprises a control unit such as a microcontroller, microprocessor, computer for controlling the power supplied to the electromagnetic motor, in particular the power supplied to the coil assembly of the electromagnetic motor. obtain. In such an embodiment, the control unit receives a position setpoint (ie representing a desired position in the object table) as an input signal, for example at an input terminal of the control unit and outputs it at an output terminal of the control unit. , For example, to generate the appropriate control signal to control the current flowing through the coil of the coil assembly. In such an embodiment, the stage device may also advantageously be equipped with a position measurement system. Such a position-measuring system provides, for example, a position signal representing the position of the object table with respect to the reference frame to the input terminal of the control unit. Examples of such position measurement systems may include, for example, interferometer-based measurement systems or encoder-based measurement systems.

[0081] In one embodiment, the magnet assembly of the electromagnetic motor according to the present invention is mounted on a magnetic member, such as a ferromagnetic member, for increasing the magnetic field strength.

[0082] It should be noted that in this context the term "continuous" or "continuously" means that no other exposure or irradiation of the target portion is carried out between steps. Is. However, this does not preclude performing other operations between steps, such as measuring steps, calibrating steps, positioning steps and the like.

[0083] Although particular reference is made herein to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein have other applications. For example, this is the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads and the like. In the context of these alternative applications, the use of the terms "wafer" or "die" herein is considered synonymous with the more general terms "substrate" or "target portion", respectively. Those skilled in the art will recognize that it may be. The substrates described herein may be processed before or after exposure with, for example, tracks (usually a tool that applies a layer of resist to the substrate and develops the exposed resist), metrology tools and / or inspection tools. be able to. Where appropriate, the disclosure herein can be applied to these and other substrate processing tools. Further, the substrate can be processed multiple times, eg, to produce a multi-layer IC, so the term substrate as used herein can also refer to a substrate that already contains multiple processed layers.

[0084] Although particular reference has been made to the use of embodiments of the invention in the field of optical lithography, the invention may also be used in other fields depending on the context, eg imprint lithography and is not limited to optical lithography. Please understand. In imprint lithography a topography in a patterning device defines the pattern created on a substrate. The topography of the patterning device is imprinted in the resist layer provided on the substrate and the resist is cured by the application of electromagnetic radiation, heat, pressure or a combination thereof. The patterning device is removed from the resist leaving a pattern inside when the resist cures.

[0085] The terms "radiation" and "beam" as used herein include not only particle beams, such as ion or electron beams, but also ultraviolet (UV) radiation (eg, 365 nm, 248 nm, 193 nm, 157 nm or 126 nm). , Or having wavelengths around these) and extreme ultraviolet (EUV) radiation (eg, having wavelengths in the range of 5 nm to 20 nm).

[0086] The term "lens", where the context allows, may refer to any one or combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic and electrostatic optical components.

Although a specific embodiment of the present invention has been described above, it is understood that the present invention can be practiced in a manner different from that described. For example, the present invention is directed to a computer program including one or more sequences of machine readable instructions describing a method as disclosed above, or a data storage medium having such computer program stored therein (eg, semiconductor memory, magnetic field). Or optical disc).

[0088] The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that the invention as described can be modified without departing from the scope of the claims.

Claims (15)

A magnet assembly configured to generate an alternating magnetic field having a magnetic pitch in a first direction;
A coil assembly including a plurality of coils configured to cooperate with the magnet assembly to generate a first force in the first direction, the plurality of coils comprising a first coil set and a second coil set. A coil assembly, wherein the first coil set first coil pitch in the first direction is different from the second coil set second coil pitch in the first direction; Bei to give a,
The first coil set and the second coil set are arranged such that the width direction of each coil of the first coil set and the width direction of each coil of the second coil set are along the same direction. Has been done,
The first coil pitch is a width of each coil of the first coil set, and the second coil pitch is a width of each coil of the second coil set,
The first coil pitch and the second coil pitch are both larger than the magnetic pitch ,
Electromagnetic motor.   The electromagnetic motor of claim 1, wherein the coils of the first coil set are arranged in one or more first coil triplets configured to be powered by a first three-phase power supply. ..   The electromagnetic according to claim 1 or 2, wherein the coils of the second coil set are arranged in one or more second coil triplets configured to be powered by a second three-phase power supply. motor. The coils of the first coil set are arranged in one or more first coil triplets,
The coils of the second coil set are arranged in one or more second coil triplets,
The one or more first coil triplets and the one or more second coil triplets are configured to be powered by a three-phase power supply, such that they are powered by the same phase of the three-phase power supply. The electromagnetic motor according to claim 1, wherein the coils of the one or more first coil triplets and the one or more second coil triplets configured as described above are connected in series.   The electromagnetic motor of claim 4, wherein a cross section of a coil winding of the one or more first coil triplets is substantially equal to a cross section of a coil winding of the one or more second coil triplets. ..   6. The coil winding height of the one or more first coil triplets is substantially equal to the coil winding height of the one or more second coil triplet coils. The electromagnetic motor as described in 1 above.   7. The electromagnetic motor of any one of claims 1-6, wherein the magnet assembly includes a plurality of permanent magnets configured to generate the alternating magnetic field having the magnetic pitch in the first direction. Pc1 <Pc2 <2Pc1, where
Pc1 = the first coil pitch,
The electromagnetic motor according to claim 1, wherein Pc2 = the second coil pitch. Pc1 = 4 / 3Pm,
Pc2 = 5 / 3Pm, where
Pc1 = the first coil pitch,
Pc2 = the second coil pitch,
The electromagnetic motor according to claim 1, wherein Pm = the magnetic pitch. A magnet assembly configured to generate a two-dimensional alternating magnetic field having a first magnetic pitch in a first direction and a second magnetic pitch in a second direction;
A coil assembly configured to cooperate with the magnet assembly to generate a first force in the first direction and a second force in the second direction, the coil assembly generating the first force. A first coil set including a plurality of first coils for generating and a second coil set including a plurality of second coils for generating the second force, and The ratio R1 of the first coil pitch of the first coil set in the first direction is the ratio of the second coil pitch of the second coil set in the second direction to the second magnetic pitch. R2 is different from the, eh Bei and coil assembly, the,
The first coil set and the second coil set are arranged such that the width direction of each coil of the first coil set and the width direction of each coil of the second coil set are along the same direction. Has been done,
The first coil pitch is the width of each coil of the first coil set, the second coil pitch is the width of each coil of the second coil set,
The values of the ratio R1 and the ratio R2 are both larger than 1 and smaller than 2.
Electromagnetic motor. Pm1 = Pm2 = Pm, where:
Pm1 = the first magnetic pitch,
Pm2 = the second magnetic pitch,
The electromagnetic motor according to claim 10, wherein Pm = magnetic pitch. Pc1 = 4 / 3Pm,
The electromagnetic motor according to claim 11, wherein Pc2 = 5 / 3Pm.   11. The plurality of first coils of the first coil set are arranged in one or more first coil triplets configured to be powered by a first three-phase power supply. 13. The electromagnetic motor according to any one of 1 to 12.   11. The plurality of second coils of the second coil set are arranged in one or more second coil triplets configured to be powered by a second three-phase power supply. The electromagnetic motor according to any one of 1 to 13. A stage apparatus configured to position an object, the stage apparatus comprising:
An object table configured to hold the objects,
15. One or more electromagnetic motors according to any one of claims 1 to 14, wherein the one or more electromagnetic motors are configured to displace the object table,
And a stage device.